@type t() :: %Milvex.Milvus.Proto.Milvus.AlterCollectionSchemaRequest.Action{
  __unknown_fields__: [Protobuf.unknown_field()],
  op:
    {:add_request,
     Milvex.Milvus.Proto.Milvus.AlterCollectionSchemaRequest.AddRequest.t()
     | nil}
    | {:drop_request,
       Milvex.Milvus.Proto.Milvus.AlterCollectionSchemaRequest.DropRequest.t()
       | nil}
    | nil
}